Need F4TE (351w) advice

Wyflyer · Jun 16, 2010

Okay, i've got this nice F4TE-1605-AA engine set aside for my 351 EFI swap. It's out of a 96 F-250. I pulled the factory intake and sure enough it has the roller cam. I recall reading a year or so back that the truck engines had lower compression. As in low 8's?
It's going to be an EFI engine. I've got a 351w lightning intake, an Explorer upper intake, and an A9L computer and a RJM harness.
It has some oil leaks so i'm planning to rebuild it just to know it has good rings, bearings, and gaskets.
So in reading other sites it seems that the factory cams were pretty good and EFI won't tolerate a lopey cam. I'm happy with stock or near stock engine due to their longevity, but I want this thing to perform well as possible without throwing a bunch of money at it. I want it to pull good on the highway, burn the tires at will, but I'm happy with the original heads, lightning intake and EFI. Which only really leaves the cam and pistons as variables.
Is there any benefit in increasing the compression with new pistons and change to another cam? If so, what do you suggest? Any other ideas?
thanks

Nightstick · Jun 16, 2010

Wyflyer said:
...I've got a 351w lightning intake, an Explorer upper intake, and an A9L computer and a RJM harness....Is there any benefit in increasing the compression with new pistons and change to another cam? If so, what do you suggest? Any other ideas?
thanks

I have no answers to your questions but I'll take all those parts off your hands;D

I'm putting together the parts to do the same swap. I don't have the roller cams but I'll work with what I have. I'm building more of a trail rig/crawler so I'll be going to an RV cam but if I was keeping mostly on the street I'd stick with the factory specs on a cam. I'm also gonna wait till the motor is torn down to decide whether or not to swap pistons. If everything looks good on the inside I'm sticking with factory. Let me also mention that I have an entire build to do not just the motor. If I had a running rig and was just building another motor to drop in I'd make it a BEAST!

needabronco · Jun 16, 2010

The compression thing shouldn't really be a concern. If it is you could use a piston with a taller deck height and raise the compression, if you go that route I would recommend hypereutectic pistons and stay between mid 8's and mid 9's for longevity. There won't be any 'real' gain in horsepower beyond a 'few' with raising the compression a point or so either. In fact most truck engines have lower compression and seem to produce more low end torque and power when compared to the comparable sedan engines. That's also part of the reason they last forever too...

As far as Cam's go, your going to be using mass air which is much more forgiving than speed density. I run a 302 firing order Performer cam with an A9P (HO/351 firing order) computer and it runs great. The biggest thing to look at is keep duration around 112 or so and under, and keep the RPM range reasonable. Seems most roller cams are mid/high rpm cams. The 351 can probably get away with it a bit more than a 5.0 or 302.

Good luck

broncnaz · Jun 16, 2010

The F4TE cam is pretty good specs are 256/266 (int/exh)- advertised not at .050. lift 422/448.
For a truck thats about the cam I would want you'll get lots of lowend for burning the tires and should cruise good on the hiway as long as gearing is correct.
Not sure on the comp ratio I thought it was around 8.5-8.8. It would be nice to be at about 9-1 or so but unless the cam you end up going with needs it. I would probably stay with what it has.
When going with the A9 computer ie mass air you can make bigger changes to cams and such its only the stock truck speed density setup that has issues with bigger cams.

vintage bronco · Jun 16, 2010

lopey cams can be used with EFI if you use mass air system if you stay with speed density is when you have to watch cam selection. SVT lightning had a marine style flat tappet cam from the factory from 1993-1995 and is speed density my 95 lightning runs very well stock.

barronj · Jun 16, 2010

My .02-

Leave the pistons alone (after you clean them up for reassembly), get a set of aluminum heads w/ 58cc chambers. That will bring your compression up some & let your motor breathe, and still be at 9:1 or under, if I had to guess. You can pick up a good set of used heads for $800 +/-. Rockers & hardened pushrods will be required then, unless you can find pedestal mount heads (your stockers are pedestal mount, and you can re-use the hardware)These are typically found w/ smaller valves (1.9" I / 1.6" E) & smaller intake runner (165cc) head style. Edelbrocks are plentiful, and perform well.

Here's your piston:

With the stock heads, you'll be at 8.5:1 or lower. There are conflicting #'s on how low the compression is on these motors, but 8.5 is the high #.

I'm running a '97 F4TE 351 with 56-57cc heads (started life as 58cc). I found a new set of AFR 185's for $800, they needed .0010 taken off the deck to clean up some damage from shipping. I'm running a small cam, and I'm *generally* happy.

rudy16 · Jun 17, 2010

I also have a 351 efi I would like to swap. Someone said I should look for a newer computer and wiring harness my 5.8 is from a 90 f150 do you guys agree. Also is there a thread on here about this swap. Sorry not trying to ruin your post.

Nightstick · Jun 17, 2010

rudy16 said:
I also have a 351 efi I would like to swap. Someone said I should look for a newer computer and wiring harness my 5.8 is from a 90 f150 do you guys agree. Also is there a thread on here about this swap. Sorry not trying to ruin your post.

Go to BC Broncos website and click on the "fuel EFI" button on the left. It has links to several EFI articles published in Bronco Driver Mag. You can also go to fordfuelinjection.com which is the website the guy who wrote those articles also publishes info on. It also has early bronco schematics and other good info.

Wyflyer · Jun 17, 2010

So how strong will it be if I just overhaul it, leave it stock and run it with factory pistons, heads, and cam?
How do they perform in these broncos as a stock engine?
I always thought they were a dog in the heavy trucks.
How about keeping the factory cam and just swapping in some 9:1 pistons? Is there any performance to be gained by messing with the ECU?

mattt · Jun 17, 2010

I would second Barronj's suggestion. You have more to gain and a better & quicker build by getting alum. heads with a smaller chamber. Your existing heads probably need some freshening up depending on the mileage. Instead of freshening old iron heads just put that $$$ towards a good set of alum heads with smaller chambers. Sure you can bump the compression by buying other pistons, but as long as the short block checks out and looks okay, there are extra benefits with the alum. heads. Lighter weight and resistance to detonation being the biggies. Bumping the compression could lead to detonation and the alum. heads will help with that.

I went basically the same way as barronj went.....just used a different cam. I looked into having my iron GT40 heads freshened up....~$400. I bought new unused GT40X heads for a little under double that.

broncnaz · Jun 17, 2010

Looking at about 210-230 hp, and around 3oo fl lbs TQ for a stock engine. Considering that most EB engines were only rated at around 140hp It will be a noticeable jump.
Bumping up the compression wont gain you much at all. one test I read about in a magazine only showed about a 10 hp differance when the compression was bumped up about a full point. In fact one of the mustang magazines on the stand right now has a similar test although they did it on a supercharged mustang and showed about a 25hp gain. Usually the main reason to bump up compression is to run a camshaft that needs more compression.
Heads will gain you some power mostly due to better flow. Considering how we tend to build are engines the power gains with aftermarket heads wont be fully realized. I'd say you probably expect about 40 hp gain from good aftermarket heads.
A ECU tune might gain you 10-15 hp but I wouldnt really bother with a stock engine if you have some mods then it would really help.

As for the 90's trucks feeling doggy I never really noticed it much but I will say that most of the newer vehicles tend to feel less powerful but I I think its due to the newer drivetrains which tend to shift softer and faster than the old tranny's.

needabronco · Jun 18, 2010

I personally wouldn't waste the money on aluminum heads if you planned to run compression less than 9:1 and were still using the stock cam and cast pistons. There just won't be any gain in performance that would be noticeable, it might be.... You might as well install a set of early 351W heads or late 60's or early 70's 302 heads.....

Now if you were planning for the whole package, and matched a new cam to the heads, ran new hypereutectic or forged pistons, ran 9.5:1-10:1 compression, new custom exhaust to match, then yes aluminum heads would be worth it...

I guess you won't really have a good indication of where to go until your mill is broken down and inspected. If your heads only need a little work, and the bores can be honed, I'd just stay stock. If the heads are wasted, and the bores need to be punched out, then that would sway me into upgrading...

hartbronco · Jun 20, 2010

needabronco said:
I personally wouldn't waste the money on aluminum heads if you planned to run compression less than 9:1 and were still using the stock cam and cast pistons. There just won't be any gain in performance that would be noticeable, it might be.... You might as well install a set of early 351W heads or late 60's or early 70's 302 heads.....

Now if you were planning for the whole package, and matched a new cam to the heads, ran new hypereutectic or forged pistons, ran 9.5:1-10:1 compression, new custom exhaust to match, then yes aluminum heads would be worth it...

I guess you won't really have a good indication of where to go until your mill is broken down and inspected. If your heads only need a little work, and the bores can be honed, I'd just stay stock. If the heads are wasted, and the bores need to be punched out, then that would sway me into upgrading...

Yes this is good advice .... I did the same I took my 1996 351w apart then put in good Hyper pistons , stock cam ,kept the heads and did some porting , punched the block 30thow ,it has 9.5:1 and it works for me , I can be in 4th gear at 650rpm and it pulls without shifting..... not bad !!!!!. I have 4:88/np435/d20and a set of 38.5 SXs. So I think you don't have to go crazy on a build to get some more bottom end torque, remember its the torque # that you should be looking for not the Horespower # .The 1996 351 has the highest tourque # at 328ft/lb@2200rpm other then the Lightnings 340ft/lb@3200rpm . The other 351s from 1980-1995 only run 310ft/lb@ 2800rpm or the (1995 only at 325ft/lb@2800rpm) . my .02

Wyflyer · Jun 20, 2010

hartbronco said:
Yes this is good advice .... I did the same I took my 1996 351w apart then put in good Hyper pistons , stock cam ,kept the heads and did some porting , punched the block 30thow ,it has 9.5:1 and it works for me , I can be in 4th gear at 650rpm and it pulls without shifting..... not bad !!!!!. I have 4:88/np435/d20and a set of 38.5 SXs. So I think you don't have to go crazy on a build to get some more bottom end torque, remember its the torque # that you should be looking for not the Horespower # .The 1996 351 has the highest tourque # at 328ft/lb@2200rpm other then the Lightnings 340ft/lb@3200rpm . The other 351s from 1980-1995 only run 310ft/lb@ 2800rpm or the (1995 only at 325ft/lb@2800rpm) . my .02

This sounds like what I have in mind. I'm not building a race car, and i'm running 33's and 3:53 gears. No problems with these pistons and valve clearance?

hartbronco · Jun 20, 2010

Your good to go .... no problems .

Wyflyer · Jun 22, 2010

I'm thinking of one of these Comp Cams, in particular the 4th one up from the bottom 1500 to 5000 rpm Part number 35-310-8.
http://www.compcams.com/catalog/COMP2010/pdf/COMP_Catalog_2010_80.pdf
Along with this piston:
http://www.summitracing.com/parts/STL-H336CP
How would these work out with GT-40 heads and F4TE 351w block?
And is an 1800 rpm much different than a 1200 off the line?

hartbronco · Jun 22, 2010

That cam looks to be for a 5.0L ?? not the 5.8L .

Wyflyer · Jun 22, 2010

woops, there i fixed it. Tell me why that cam won't run in a 351w?

barronj · Jun 22, 2010

hartbronco said:
That cam looks to be for a 5.0L ?? not the 5.8L .

As long as it's the 5.0 HO firing order, it will slip right in a 5.8 no sweat.

HOWEVER, as long as you're putting a new bumpstick in, put heads on! It's a natural progression. The difference between a '96 F4TE motor putting out 200hp & 400hp is all in the head/cam combo.

barronj · Jun 22, 2010

Wyflyer said:
This sounds like what I have in mind. I'm not building a race car, and i'm running 33's and 3:53 gears. No problems with these pistons and valve clearance?

With the size of the dish you have on the stock pistons, barring severely mis-cuing your cam (installing it way advanced or retarded, instead of straight up & down), I would venture to say you're safe to run 2.02 valves & healthy lift/duration #'s, if you wanted to push the envelope there.

Need F4TE (351w) advice

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